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7f9a33dba1
This simplifies the ownership model and makes Region easier to reason about. Userspace Regions are now primarily kept by Process::m_regions. Kernel Regions are kept in various OwnPtr<Regions>'s. Regions now only ever get unmapped when they are destroyed.
94 lines
2.6 KiB
C++
94 lines
2.6 KiB
C++
#pragma once
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// KBuffer: Statically sized kernel-only memory buffer.
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//
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// A KBuffer is a value-type convenience class that wraps a NonnullRefPtr<KBufferImpl>.
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// The memory is allocated via the global kernel-only page allocator, rather than via
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// kmalloc() which is what ByteBuffer/Vector/etc will use.
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//
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// This makes KBuffer a little heavier to allocate, but much better for large and/or
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// long-lived allocations, since they don't put all that weight and pressure on the
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// severely limited kmalloc heap.
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#include <AK/Assertions.h>
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#include <AK/LogStream.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/Region.h>
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class KBufferImpl : public RefCounted<KBufferImpl> {
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public:
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static NonnullRefPtr<KBufferImpl> create_with_size(size_t size)
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{
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auto region = MM.allocate_kernel_region(PAGE_ROUND_UP(size), "KBuffer", false, false);
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ASSERT(region);
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return adopt(*new KBufferImpl(region.release_nonnull(), size));
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}
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static NonnullRefPtr<KBufferImpl> copy(const void* data, size_t size)
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{
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auto buffer = create_with_size(size);
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memcpy(buffer->data(), data, size);
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return buffer;
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}
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u8* data() { return m_region->vaddr().as_ptr(); }
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const u8* data() const { return m_region->vaddr().as_ptr(); }
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size_t size() const { return m_size; }
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size_t capacity() const { return m_region->size(); }
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void set_size(size_t size)
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{
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ASSERT(size <= capacity());
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m_size = size;
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}
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private:
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explicit KBufferImpl(NonnullOwnPtr<Region>&& region, size_t size)
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: m_size(size)
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, m_region(move(region))
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{
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}
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size_t m_size { 0 };
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NonnullOwnPtr<Region> m_region;
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};
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class KBuffer {
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public:
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static KBuffer create_with_size(size_t size)
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{
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return KBuffer(KBufferImpl::create_with_size(size));
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}
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static KBuffer copy(const void* data, size_t size)
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{
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return KBuffer(KBufferImpl::copy(data, size));
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}
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u8* data() { return m_impl->data(); }
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const u8* data() const { return m_impl->data(); }
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size_t size() const { return m_impl->size(); }
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size_t capacity() const { return m_impl->capacity(); }
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void set_size(size_t size) { m_impl->set_size(size); }
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const KBufferImpl& impl() const { return m_impl; }
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KBuffer(const ByteBuffer& buffer)
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: m_impl(KBufferImpl::copy(buffer.data(), buffer.size()))
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{
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}
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private:
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explicit KBuffer(NonnullRefPtr<KBufferImpl>&& impl)
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: m_impl(move(impl))
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{
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}
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NonnullRefPtr<KBufferImpl> m_impl;
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};
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inline const LogStream& operator<<(const LogStream& stream, const KBuffer& value)
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{
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return stream << StringView(value.data(), value.size());
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}
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